Short confusing example with unicode, print, and __str__

[Gerard Brunick]

I really don't understand the following behavior:
.... def __init__(self, s): self.s = s
.... def __str__(self): return self.s
....Print using just c: Traceback (most recent call last):
File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in
position 3: ordinal not in range(128)Traceback (most recent call last):
File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in
position 3: ordinal not in range(128)

Why would "print c.s" work but the other two cases throw an exception?
Any help understanding this would be greatly appreciated.

Thanks in advance,
Gerard